Python Language Tutorial => Alignment and padding

The format() method can be used to change the alignment of the string. You have to do it with a format expression of the form :[fill_char][align_operator][width] where align_operator is one of:

• < forces the field to be left-aligned within width.
• > forces the field to be right-aligned within width.
• ^ forces the field to be centered within width.
• = forces the padding to be placed after the sign (numeric types only).

fill_char (if omitted default is whitespace) is the character used for the padding.

'{:~<9s}, World'.format('Hello')
# 'Hello~~~~, World'

'{:~>9s}, World'.format('Hello')
# '~~~~Hello, World'

'{:~^9s}'.format('Hello')
# '~~Hello~~'

'{:0=6d}'.format(-123)
# '-00123'